1. Technical Field
The disclosure generally relates to buck converters, and particularly to a buck converter with an overcurrent protection function.
2. Description of Related Art
A buck converter commonly has an overcurrent protection function to prevent a load connected to the buck converter from being damaged due to overcurrent input into the load. The buck converter usually includes a pulse-width modulation (PWM) controller. The PWM controller detects an output voltage of the buck converter, compares the detected output voltages with a corresponding preset voltage, and determines whether a corresponding output current of the buck converter is greater than a current protective threshold of the load according to the comparison.
However, the output voltage of the buck converter is based on an ideal state that resistances of electronic elements, such as switches and an inductor of the buck converter, are unchangeable. Actually, the electronic elements of the buck converter have reversible temperature coefficients. That is the resistances of the electronic elements increase as the temperature increases. When the temperature is high, the detected voltage is greater than the preset voltage because of the actually increased resistances of the electronic elements. Therefore, although the output current does not exceed the current protective threshold, the PWM controller may mistakenly determine the output current is greater than the current protective threshold and execute an unnecessary protective process.
Therefore, there is room for improvement within the art.